Timing apparatus



Feb. 9, 1960 A. H. MIDGLEY ErAL 2,924,067

TIMING APPARATUS Filed Jan. 3, 1955 2 Sheets-Sheet l Feb. 9, 1960 A. H. MIDGLEY ETAL 2,924,067

' TIMING APPARATUS Filed Jan. 3, 1955 2 Sheets-Sheet 2 United States Patent 2,924,067 TIMING APPARATUS Albert Henry Midgley and Albert Mon-ell Midgley, Northwood, England Application January 3, 1955, Serial No. 479,446

Claims priority, application Great Britain January 11, 1954 3 Claims. (Cl. 5821.14)

This invention relates to timing apparatus and has for its main object to provide an improved form of interval timing mechanism which is economical to produce and which is suitable for use in electric cookers or other devices.

The invetion accordingly consists in an interval timing mechanism for use inelectric cookers or other devices for actuating an alarm and/or an electric switch at the end of a predetermined time interval under the control of a clock wherein such timing mechanism is normally disconnected from the clock mechanism but is so arranged as to be automatically placed in operative association with such clock mechanism by the actuation of the device provided for setting the mechanism and determining the time interval. According to the preferred arrangement, means are provided whereby the mechanism automatically effects the actuation of a continuous alarm at the end of the predetermined time interval, and the apparatus for operating the alarm is controlled by the device provided for setting the mechanism and is so arranged as to be rendered inoperative by the restoration of such device to its normal position.

Preferably, the device provided for setting the mechanism comprises a setting spindle which is normally locked against rotation by spring means but which is movable longitudinally so as to be rotatable into a predetermined set position, said setting spindle carrying a gear wheel which is automatically moved by the longitudinal movement of the spindle into engagement with a gear wheel operatively associated with the clock mechanism whereby the setting spindle is automatically returned to normal at the speed of the clock, said setting spindle being also provided with means for auto matically actuating an alarm device and/or for closing or opening an electric switch when the setting spindle completes its rotary return movement at the end of the predetermined time delay.

I The invention will be more completely understood from the following detailed description which is given in conjunction with the accompanying drawings in which:

Figure 1 is a front view of a clock embodying an interval timing mechanism constructed in accordance with the invention, and suitable for use on an electric cooker or other device;

Figure 2 is a plan view of the clock showing the'interval timing mechanism in the normal position;

Figure 3 is a plan view of the clock showing the interval timing mechanism in the set position;

' Figure 4 is a plan view of the clock showing .the interval timing mechanism on reaching the alarm position at the end of the delay period; and

Figure 5 is a fragmentary front view of the hammer mechanism employed for actuating an alarm bell.

Referring now to these drawings, the clock is constructed in any suitable manner having an hour hand 1, a minute hand 2, and an indicator hand 3 mounted on a central spindle in front of a dial or clock face 4, surrounded by an annular plate 5 carrying the clock numbers. This clock is driven by a synchronous motor 6 through a gear train of suitable well-known form which is mainly mounted between a pair of spaced metal plates 7 and 8, one of which 7 carries the synchronous motor 6, and the other of which 8 carries three forwardly projecting posts 9 on which is mounted a third metal plate 10 which serves as a base plate for the clock face '4, the metal plates 7 and 8 being spaced apart by four posts 11. The synchronous motor 6 is preferably permanently connected up, so that the clock is always in operation when the cooker or other device to which it may be applied, is connected to a suitable source of power, and in addition to the hour and minute hands, the clock is provided with a seconds hand, in order to show at a glance that the clock is in operation.

The mechanism for effecting the actuation of an alarm device a predetermined time after being set comprises a slidably arranged spring loaded spindle 12 which projects through the clock face, and carries three wheels 13, 14, 15. All these wheels move longitudinally with the spindle 12 and while the two outer wheels 13 and 15 are gear wheels the centre wheel 15 is a plain wheel carrying a stud 16 on one face which normally projects through a slot 17 in the fixed plate 8 so as to lock the mechanism in its normal position. One of the outer gear wheels 13 meshes with a pinion 18 which drives through gear wheels 19 and 20 on to the indicator hand 3 on the clock face so that the latter can be set to any desired position by depressing and rotating the spindle 12 and is designed to register the time delay required in minutes while the aforesaid pinion 18 is also operatively connected to a movable indicator dial 21 which is arranged behind a window 21a in the clock face 4 and is adapted to register the time delay required in hours, the gear train being so arranged as to cause the indicator 21 to increase its index figure once for each complete revolution of the indicator hand. The other outer gear wheel 15 on the setting spindle 12 is adapted when the spindle is depressed to mesh with a pinion 22 which is keyed to a spindle 23 carrying a gear wheel 24 rotated by the clock mechanism, so that after the device is set for the required delay the clock mechanism rotates this last mentioned gear wheel 24 and in so doing rotates the setting spindle 12 together with the first outer gear wheel 13 and returns the mechanism to normal at the speed of the clock. In order to facilitate this operation, the gear wheel 15 is mounted on the setting spindle 12 for free rotation in order to permit the spindle 12 to rotate the setting mechanism while the gear wheel 15 remains stationary, but this gear wheel 15 is pressed against a collar 25 by a leaf spring 26 so designed as to provide a sufiicient frictional torque to enable the gear wheel 15 to drive the spindle 12'when it is acted upon by the pinion 22 controlled by the clock mechanism. On reaching the normal position, the stud 16 on the plain wheel 14 registers with the slot 17 in the fixed plate 8 and thus allows the spindle to fly back into the position shown in Figure 4 under the action of the controlling leaf spring 27 and actuate an alarm bell by any suitable form of mechanism which may be so designed as to give the bell a single ring or operate the bell continuously by means of a hammer mechanism, as shown in Figure 5 in which the arm 29 of the bell hammer 30 is attached to a bell-crank lever 31 carrying a toothed projection 32 which is acted upon by the spring 34, so as to ride on the surface of a continuously rotating notched wheel 33 during the time that the setting spindle 12 is in the ringing position shown in Figure 4. It will be seen however that thebel-l-crank lever 31 is controlled by the lever 35 which is in turn controlled by a collar 36 disposed on the rear end of the setting spindle 12. This collar 36 slides in an aperture in the metal plate 7, and is provided on one side with a notch 37 with which the side of the lever 35 engages when thespim dle 12 moves into the ringing position so as to allow the bell-crank lever 31 to swing into its operative position under the action of its controlling spring 34. When however the spindle 12 is pushed inwards for the purpose of setting the interval timing mechanism, the lever 35 is forced out of the notch 37 and is thus swung sideways so as to swing the bell-crank lever out of "its operative position, and a similar action also occurs when the setting spindle 12 is pulled outwards into its normal position after the alarm has begun to operate. Thus the setting spindle has three longitudinal positions, viz. a normal position in which it is as far forward as possible (Figure 2), a setting position in which it is pushed in as far as possible prior to rotation (Figure 3) and a ringing position, in which it is midway between the normal and the setting position. As explained above, the spindle is automatically moved into theringingposition by the spring 27 at the end of the delay period, and the force exerted by the spring is so arranged that the spindle is arrested in the position by the lever 35 when the latter snaps into the notch 37 in the collar 36, and the spindle is thus held in this position until it is pulled back to normal by the operator so as to stop the alarm. If, desired, the movement of the spindle '12 may also be arranged to operate a switch controlling a heating element, so that'such element maybe automatically switched on or off at the end of thedelay period. The gearing is so arranged that the indicator hand 3 moves synchronously with, but in the opposite direction to, the minute hand 2 of the clock while the indicator dia-l 21 moves synchronously with, but in the opposite direction to, the hour hand 1 of the clock so that by means of this arrangement, the mechanism can be set for any predetermined time interval, according to the capacity of the dial and as soon as it is set it will start to return to normal under the direct control of the continuously moving clock.

A small lug 38 is provided on the inner face of the plate 8 which is adapted to engage with the stud 16 on the plain wheel 14 when the indicator is turned to its full extent so as to arrest the said rotary movement of the spindle 12.

It will thus be seen that by means of this arrangement a single composite unit is provided in which an interval timing mechanism and a clock are combined, and so arranged that the interval timing mechanismis actuated by the gear train of the clock, but is disconnected from such gear train except during the time when it is actually in operation.

The whole unit may be easily mounted in the panel of an electric cooker in any conspicuous position and the various visible parts may be suitably coloured or ornamented as desired,

While the invention is mainly applicable to electric cookers or other domestic appliances however, it is to be understood that it may be readily applied toother forms of equipment either in the domestic or the'manufacturing field when it is desired to bring about the automatic actuation of an alarm, a switch, or a mechanical device after a predetermined time delay.

We claim:

1. A clock for use in'electric cookers and other devices for bringing about the operation of a "continuous alarm after a predetermined time delay, comprising in combination an electric motor for driving the clock, an interval timing mechanism provided with a setting spindle for setting the mechanism and determining the time interval, means for normally holding said spindle locked against rotation and means for permitting said spindle to be moved longitudinally into a forward position so as to be rotatable into a predetermined set position, said spindle carrying a gear wheel which is automatically moved by the longitudinal movement of the spindle into engagement with a gear wheel operatively associated with the clock mechanism, whereby the spindle is automatically returned to normal at the speed of the clock, means for driving back saidspindle longitudinally at the end of the set time interval, means for arresting such longitudinal movement at a position intermediate the forward and normal positions of the spindle, means for causing said electric motor to effect the mechanical operation of said continuous alarm while said spindle is in said intermediate position, and means for-rendering said continuous alarm inoperative by the restoration of said spindle to its normal position.

2. A clock for use in electric cookers and other de, vices {or bringing about the operation of a continuous alarm :mechanisrn after a predetermined time delay, cqmprisingin combination an electric motor for driving the clock, an interval timing mechanism provided with a setting spindle for setting the mechanism and determining the time interval, means for normally holding said spindle locked against rotation and means for permitting said spindle to be moved longitudinally into a forward position so. as to be rotatable into a predetermined set position, said spindle carrying a gear wheel which is automatically moved by the longitudinal movement of the spindle into engagement with a gear wheel operatively associated with the clock mechanism, whereby the. spindle is automatically returned to normal at the speed of the clock, means for driving back said spindle longitudinally at the end of the said time interval, said spindle having a collar which co-operates with a spring loaded locking lever controlling said continuous alarm mechanism and which has a notch on one side with which said lever engages so as to arrest the longitudinal .return movement of said spindle at a position intermediate its normal and forward positions and free said alarm mechanism for continuous operation by said electric motor until said locking lever is disengaged from said notch by the withdrawal of said spindle to its'norma-l position.

3. A clock according to claim 2 wherein said alarm device comprises a, bell hammer carried on one arm of a'spring loaded bell-crank lever having a toothed projection which rides on a notched wheel driven by the clock mechanism so as to execute a vibratory movement, and wherein said spring loaded locking lever co-operates with the other arm of said bell-crank lever so as to hold said. toothed projection out of contact with said notched wheel except when said locking lever is in operative cut with the notch in the collar of said setting spindle.

References Cited in the file of this patent UNITED STATES PATENTS 1,975,347 Browning Oct. 2, 1934 2,200,110 Anderson May 7, 1940 2,421,986 Bohman June 10, 1947 2,545,617 Kaefer et al Mar. 20, 1951 2,592,024 Goodroad et al Apr, 8., 1952 

